Sustained release of prednisone and mesalamine from diatom exoskeletons : bioinspiration for the development of safe oral drug delivery devices to tackle gastrointestinal diseases

Abstract

Mesoporous silicon and silica-based particles have recently been synthesized and proposed for the controlled delivery of several drugs [1,2]. On the other hand, nature and in particular marine organisms have been the source and inspiration for the development of different biomedical applications, including drug delivery devices [3]. On the border of both rests diatoms exoskeletons, nature-made porous silica-based microparticles with amazing morphological features, promising a high potential in drug delivery. Nevertheless, its safety and drug permeability on oral formulations have not yet been studied. In this study, we have demonstrated that diatoms silica microparticles (DSM) have almost no toxicity in colon cancer cells Caco-2, HT- 29, HCT-116 and Caco-2/HT-29, even at concentrations as high as 1000 μg/mL. Moreover, the delivery profile of two common drugs to address gastrointestinal diseases, mesalamine (antiinflammatory) and prednisone (glucocorticosteroid). DSMs are able to release prednisone in a controlled manner and change its absorption pattern, which may improve the safety of its administration. In addition, DSMs can enhance the permeation of mesalamine. These results confirm the potential of DSMs for the development of oral formulations for the therapy of gastrointestinal diseases.